The East European Plain is part of the East European Platform. This is an ancient and stable block, bordering with folded belts. In the east, the platform is framed by the Urals. The tectonic structure of the East European Plain is such that in the south it is adjacent to the Mediterranean fold belt and the Scythian plate, which occupies the space of Ciscaucasia and Crimea. The border with it runs from the mouth of the Danube, along the Black and Azov Seas.
Tectonics
The complex tectonic structure of the East European Plain has been studied by many scientists. Foreign experts call it Russian (just like a platform). Part of its southern border runs through the Tsimlyansk reservoir region . Here is a large geological anomaly - the Main East European fault. The structure of the platform on this site is very complex, as it protrudes with wedges into the Scythian plate.
Due to the colossal area, the tectonic structure of the East European Plain is uneven. Scientists distinguish two large shield-ledges (Ukrainian and Baltic), as well as several areas of shallow and deep basement. It is composed of Archean, Lower Proterozoic, and deeply metamorphosed formations.
Archean layers
The multi-tiered tectonic structure of the East European Plain is such that the foundation is exposed in the area of the Baltic Shield in Karelia and on the Kola Peninsula. The same is observed with the Archean layer in the Konotop, Podolsky and Dnieper massifs. Here it is represented by amphibolites, migmatites and gneisses. In these rocks there are many accumulations of ferruginous quartzites and graphite. Their age is about 3 million years.
Another example of the Archean layer is the Voronezh anteclise, where the foundation is laid at a not very great depth. It consists of volcanic and femic formations. These rocks are distinguished by a large number of intrusions of acidic and basic composition, whose age is about 2.7 million years.
Lowering and raising
Basically, the territory of the East European Plain is a platform cover, which is composed of deposits of the Proterozoic, Paleozoic, Mesozoic and Cenozoic era. The foundation of the Russian plate is characterized by an uneven relief of the foundation roof. Four main zones of subsidence and uplift are distinguished in its structure. They alternate with each other. These are the Caspian lowering zone, the Sarmatian uplift zone, the Baltic-Central Russian lowering zone and the Baltic uplift zone.
On average, the platform capacity is from 35 to 40 kilometers (the maximum power recorded in the Voronezh anteclise is 55 kilometers, where there is a thickened basalt layer). The minimum figures refer to the Caspian syneclise. The rise of the basalt layer has led to a thinning of the earth's crust in the Pachelm aulacogen.
Caspian massif
The approximate age of the East European Plain is 1.6-2.6 million years (its oldest sites are located in the eastern part). The old massifs include Tatar, Caspian and Zhigulevsk-Pugachevsky. They are separated by a protoplatform cover. The largest massif is the Caspian. Wells are present in Samara Volga and Saratov Volga. High-alumina Archean gneisses and shales were discovered in them.
The Caspian massif, due to which the height of the East European Plain is determined at its southeastern borders, has a specific deep structure. There is no granite layer in its center, but there is a rise in basalt at the Aralorsky and Khobdinsky gravity maxima. Another picture develops on the outskirts of the massif. There is a thinned layer of granite.
The Caspian syneclise includes many salt domes. On its western and northern sides there are deep faults (Volgograd step, Zhadovsky ledge, Tokarev flexure). The foundation is lowered to a depth of 25 kilometers. Salt domes are most developed in the Guryev zone. Their sizes can be hundreds of square kilometers. They have a triangular, rounded and even elliptical shape. The largest salt domes are Chelkarsky, Dossorsky, Indersky, Makatsky, Elton and Sakharno-Lebyazhinsky.
Syneclises and anteclises
Moscow syneclise is the largest on the Russian platform. Such in its central part is the East European Plain. Photos and studies by geologists show that on its northern side there are two uplifts (Soligalichsky and Sukhonsky). The most lowered part of the syneclise is located not far from Syktyvkar, where several salt domes (Seregovsky domes) composed of Devonian salt can be traced. Its base is the Central Russian aulacogen, filled with sediment.
Another important tectonic element of the plain is the Volga-Ural anteclise. It consists of large depressions and uplifts. The anteclise has a complex structure. Its main uplift is the Tokmovsky arch in Mordovia. The key waterway of the region, the Volga, flows along the anteclise. Other large rivers of the East European Plain (Don, Dnieper, Western Dvina) are inferior to it in the basin area and other characteristics.
Relief
The average height of the East European Plain is 170 meters. The highest indicator was recorded on the Ural Upland in Tatarstan (479 meters). In general, the relief of the plain varies depending on the region. Its central part is divided into several alternating lowlands and elevations. The first of them is located in the Oka Valley, north of the Donetsk Ridge. This is the Central Russian Upland. During the Dnieper glaciation, it was covered with a glacier. This is evidenced by characteristic deposits, including moraine on the right bank of the Oka, not far from Serpukhov.
The Bugulmino-Belebeyevskaya Upland is located in the Urals. This is a hilly and bumpy plateau. It is composed of siltstones, limestones, clays, marls and sandstones. There are many karst dips and caves. The erosive relief is divided by rivers - tributaries of the Volga, Kama and Belaya. The hill is rich in oil fields (Romashkinskoye, Tuimazinskoye, Shkapovskoye). The gentle slopes are forested weaker than the tops of the syrts.
Volga Upland
On the right bank of the Volga begins the Volga Upland. It stretches from Volgograd to Nizhny Novgorod, and in the west it is adjacent to the Tambov lowland. The relief of the East European Plain in this part was formed as a result of the destruction of rocks, after which clays, sands, chalk, marl and flask formed here. All these deposits belong to the Paleogene, Jurassic and Cretaceous.
Older and harder Permian and Carboniferous limestones come to the surface on the shores of Samara Luka. Among the sediments, strong sandstones should also be distinguished. The crystalline basement of the Volga Upland is lowered to a great depth (about 800 meters).
The closer to the Oka-Don Lowland, the more the surface decreases. The Volga slopes are steep and dissected by numerous ravines and gullies. Because of this, rugged terrain formed here.
General Syrt and the Oka-Don Lowland
Common Syrt is another important component of the relief that distinguishes the East European Plain. Photos of this region on the border of Russia and Kazakhstan show the region of chernozem, chestnut soils and salt marshes, prevailing on the watersheds and in river valleys. General Syrt begins in the Volga region and extends for 500 kilometers eastward. It is mainly located in the interfluve of Greater Irgiz and Lesser Irgiz, in the east adjacent to the Southern Urals.
Between the Volga and Central Russian Uplands is the Oka-Don Lowland. Its northern part is also known as Meshchera. The northern border of the lowland is the Oka. In the south, its natural frontier is the Kalach Upland. An important part of the lowland is the Oksko-Tsninsky rampart. It stretches through Morshansk, Kasimov and Kovrov. In the north, the surface of the Oka-Don Lowland was formed from glacial deposits, and in the south, its base is sands.
Valdai and Northern Uvaly
The vast East European Plain lies between the Atlantic and Arctic Oceans. The river basins flowing into them begin on the Valdai Upland. Its highest point is 346 meters. Valdai is located in the Smolensk, Tver and Novgorod regions. It is characterized by hilly, ridged and moraine relief. There are many swamps and lakes (including Seliger and Upper Volga Lakes).
The northernmost part of the East European Plain is the Northern Uvaly. They occupy the territory of the Republic of Komi, Kostroma, Kirov and Vologda regions. The hill consisting of hills gradually decreases northward until it abuts against the White and Barents Seas. Its maximum height is 293 meters. Northern Uvaly - the watershed of the basin of the Northern Dvina and Volga.
Black Sea Lowland
In the south-west, the East European Plain ends with the Black Sea Lowland, located on the territory of Ukraine and Moldova. On the one hand, it is bounded by the Danube Delta, and on the other, by the Azov River Kalminus. The Black Sea Lowland consists of Neogene and Paleogene sediments (clays, sands and limestones). They are overlain by loam and loess.
The lowland is crossed by the valleys of several rivers: the Dniester, the Southern Bug and the Dnieper. Their shores are characterized by steepness and frequent landslides. There are many estuaries on the sea coast (Dniester, Dnieper, etc.). Another recognizable feature is the abundance of sand spits. In the Black Sea lowland, a steppe landscape with dark chestnut and chernozem soils prevails. This is the richest agricultural granary.